Halogenosilanes are prepared from an organohalogenosilane and an organopolysiloxane as the starting materials by subjecting them to an intermolecular redistribution reaction in the presence of a monohydrochloride of a hexaalkylphosphotriamide. The thus prepared halogenosilanes, which are different from the starting halogenosilane reactant, are very useful in the silicone industry.